Yes they do from what I have seen. For example,the last official release RUU_TITAN_SPRINT_WWE_2.17.651.0_RS_TITAN_SPCS_1.47 .01_Ship included a file in it called PPST_070821_7500_SPCS_1.24_PRL60610.sa.CAB which contains 60610.prl.
The short-lived 2.16 had PRL 60610 and 2.09 had PRL 60608.
EDIT: If you have your MSL (unlock) code for your phone, you can update your PRL manually. All the latest PRLs can be found at
http://www.corolada.com/prl/. I updated mine to 60711 a while back.